Additive manufacturing techniques such as three-dimensional (3D) printing, relate to techniques for making 3D objects of almost any shape from a digital 3D model through additive processes, in which 3D objects are generated on a layer-by-layer basis under computer control. A large variety of additive manufacturing technologies have been developed, differing in build materials, deposition techniques and processes by which the 3D object is formed from the build material. Such techniques may include applying ultraviolet light to photopolymer resin, melting semi-crystalline thermoplastic materials in powder form, and electron-beam melting of metal powders.
Additive manufacturing processes usually begin with a digital representation of a 3D object to be manufactured. This digital representation is virtually sliced into layers by computer software or may be provided in pre-sliced format. Each layer represents a cross-section of the desired object, and is sent to an additive manufacturing apparatus, that in some instances is known as a 3D printer, where it is built upon a previously built layer. This process is repeated until the object is completed, thereby building the object layer-by-layer. While some available technologies directly print material, others use a recoating process to form additional layers that can then be selectively solidified in order to create the new cross-section of the object.
3D printing systems utilise build materials (also known as additive manufacturing build materials), often containing powder materials, i.e. materials formed by powder particles, which are fused together during the printing process. Build materials may also contain paste material, slurry material or liquid material. These powder materials may be transported both during the printing process and after the printing process such as when excess powder material is removed from around a printed component or part. The excess powder may be recycled for use in a future printing process.
The build material is usually provided in a source container from where it needs to be transferred to the building area or building compartment of the additive manufacturing apparatus where the actual manufacturing takes place. Movement of such materials may be performed through aspiration techniques. However, the movement of particulate build matter within such aspiration systems may generate static electricity due to the friction of high-velocity particles. It is desirable to reduce the build-up of static electricity within the build material containers of such systems.
U.S. Pat. No. 6,283,320 B1 (Patch Roger [US]) describes a container for volatile liquids, such a gasoline, made of a conductive plastic material. US 2014/0270594 A1 (Holdstock, Paul [GB] et al) describes a system for decreasing electrostatic discharges to reduce the potential for incendiary discharges caused by electrostatic charges in flexible containers. U.S. Pat. No. 5,759,649 A (Dinter Peter [DE] et al) describes a plastic packaging container with improved ability for electrostatic charge derivation.